Generally, electrical connection networks comprise metal electrical connection tracks, local metal connection zones, and possibly metal vias passing through the substrate boards. These electrical connection networks, and optionally other metal portions, form metal masses that are irregularly distributed over the surface and possibly in the interior of the substrate boards.
In the case where certain connections of the electrical connection networks are intended to transfer high-frequency signals, such as video signals, zones near these connections must be free from metal portions in order to prevent electromagnetic interference. The irregularity of the distribution of these metal portions over the substrate boards is then further accentuated.
This results in such substrate boards deforming (warping or sagging), causing planarity defects that result in local electrical connection zones not being coplanar. Integrated-circuit chips mounted on the substrate boards, by way of electrical connection elements such as balls, metal pads or electrical connection wires, in these local electrical connection zones, run the risk of having electrical connections that are defective or missing.
There is a need in the art to reduce the above drawbacks.